When a vehicle is flying at a low velocity, the various aerodynamic surfaces are not very effective. For example, when an airplane stalls, it is flying at such a low velocity that it becomes uncontrollable. A further example is that of a vertical launch of a missile from a ship or from a ground launcher. Vertical launches are desirable since the launching equipment takes far less space on the ship than if the missile were to be launched from a turret launcher and since the missile can turn to any direction, once it has cleared the superstructure of the ship.
FIG. 1, to which reference is now made, illustrates the flight of a missile 10 which is launched from a ship 12 having superstructure 14. In order to avoid the superstructure 14, the missile 10 must rise above the superstructure 14 and, only afterwards, turn towards the direction of the target 18. The missile 10 also reduces its altitude so that it comes to fly above sea level 19 at the same altitude as target 18. FIG. 1 illustrates the flight path of the missile.
FIG. 1 also shows a radar system 20, or any other tracking system, which tracks the target 18. It is typically desirable to have the missile 10 come to align its flight path with the target line of sight direction (i.e. the "boresight") of the radar system 20. The alignment is shown at 22.
The missile is first shot vertically out of the launcher 24, most of which is located below the deck, and the control system takes over only after a given period of time. Unfortunately, the missile is then flying at a low velocity, which is a relatively difficult state to control.
U.S. Pat. No. 5,082,202 describes a jet vane thrust vector control unit for use in steering a vertically launched missile during its turn towards alignment with the line of sight direction of the radar system 20. The control unit of U.S. Pat. No. 5,082,202 is jettisoned when it is no longer needed. U.S. Pat. No. 5,082,202 does not provide a control system for controlling the missile during the above-described initial launch stages.